Sensor for pH determination

Citation

(2000), "Sensor for pH determination", Sensor Review, Vol. 20 No. 2. https://doi.org/10.1108/sr.2000.08720bad.016

Sensor for pH determination

Sensor for pH determination

Keywords: Sensors, Optical sensors

Applicants: Joseph Berger (CH), Ciba Geigy AG (CH), Marizel Roilly (CH), Adrian Waldner (CH), Dirk Beckelmann (DE), Steven Mark Barnard (US)Patent number: WO9747966Publication date: 18 December 1997Title: Optical sensor system for pH determination independently of the ion strength using fluorescein bound to a polymer via a urethane and/or urea group

The invention relates to an optical sensor system for pH determination independently of the ion strength which comprises a solid polyurethane, polyurea-urethane or polyurea composition containing pH-sensitive fluorescein bound via a urethane and/or urea group in the form of a membrane on a transparent support material. The invention also relates to an optical fluorescence method which permits high-accuracy pH determination independently of the ion strength of the measurement solution. The method is particularly suitable for determining the pH of physiological solutions, in particular for determining the pH of blood. It has now been found that selection of very particular polyurethane compositions in combination with a fluorescein dye which is bound to the polymer via a bridging group and a urea group or directly via a urea group allows the production of an optical pH sensor which permits measurements of high accuracy in the physiological pH range from 6.5 to 8.2 independently of the ion strength, making a second measurement and the calculation step for eliminating the ion strength superfluous. It is essential here that the fluorescent dye is bonded to the polymer in only small amounts.